Plant Diversity of the Damietta Branch, River Nile, Egypt: An Ecological Insight

Damietta Branch; one of the two main branches of the River Nile has a length of about 242 km with an average width of 200 m and depth varying between 12 and 20 m. It receives polluted waters from different sources including industrial, agricultural and urban sewage that are causing serious environmental impacts on its vegetation and freshwater. The total number of plant species in the study area is 70, belonging to 54 genera and related to 30 families. These species can be classified ecologically into four major groups, three submerged hydrophytes, six floating hydrophytes, seventeen emergent species and 44 canal bank species. On the basis of duration, the recorded 70 species are grouped into two categories: perennials (46 species) and annuals (24 species). Hydrosoil and water variables which significantly correlated with the abundance and distribution of vegetation groups are soil texture (sand and silt), water-holding capacity, electrical conductivity, soluble anions (chloride and sulphate), total phosphorus and extractable cations (sodium, calcium and magnesium). The successive changes of the macrophytic plant vegetation in the Damietta Branch are frequently results from human activities which are causing considerable change in the hydrosoil and water chemistry, factors linked with species changes.